Manufacture of vacuum tube grids



Oct. 6, 1964 R. MAHR ETAL 3,151,636

, MANUFACTURE OF VACUUM TUBE GRIDS Filed May 2, 1960 2 Sheets-Sheet 1 FE'y I I [i INVENTORS POX 11/4/70? AN! BY (7/4/1155 WZ/A/DSZ/EY Oct. 6, 1964 R. MAHR ETAL MANUFACTURE OF VACUUM TUBE GRIDS 2 Sheets-Sheet 2 Filed May 2. 1960 INVENTORS Kor MAM? 4N0 BY (k /4x455 fill/M2515) United States Patent 3,153,636 Mist "UFAC'I'URE 9F VACUUM TUBE GEES Roy Mahr, Harrison, and Charles W. Lindsley, (Jresskill, Null, assignors to Radio Corporation of America, a corporation of Delaware Ffied lviay 2, 1536 3, el. No. 26,282 3 Qlaims. (ill. 149-715) This invention relates to improved apparatus for and method of continuously winding vacuum tube grids, and more particularly, to such apparatus and method for severing the grid lateral wire after each grid in a stick of grids has been wound, and automatically starting the winding of the next grid in the stick of grids without having loose lateral wire between grids on a finished stick.

A continuous process of winding a stick of grids comprises movin a pair of grid lateral supports or side rods, usually of relatively heavy gauge copper wire, uniformly in the direction of their lengths and at the same time rotating the side rods about an axis between them and parallel thereto. As the side rods are rotated and advanced, they are notched in a direction more or less perpendicular to their lengths and at uniform intervals. A lateral wire, usually of light gauge molybdenum is fed laterally to the side rods in such manner that the lateral wire enters a notch in a side rod. The notch is peened over, holding the lateral wire in the side rod notch, causing the lateral wire to feed, and to enter the successive notches in the two side rods. In this way, a helix of lateral wire is wound on the side rods.

At the end of an individual grid, the notching and ecning wheels are withdrawn from their operative posh tion, but the side rods continue to be fed forward and to rotate. To save grid lateral wire, the lateral Wire is roken just after the last notch comprising an individual grid is peened. The side rods continue to be advanced, after they have been advanced far enough to produce sufficient unnotched leg portions for an individual grid, the notching and peenin means are returled to their operative position, and notching and peening of the side rods is resumed. The broken end of the grid lateral wire e ers the first notch of the next individual grid of the stick of grids, and it is peened therein and the process is repeated. After the winding is completed, the grids are sized by being stretched laterally to proper size over a mandrel and the 1 ividual grids are cut apart at the unpeened portions of the side rods.

In the present process of winding grids in the manner noted above, the lateral wire is broken ofif merely by holding or clamping it just after the lateral wire enters the last notch of the individual grid, while continuing to rotate the side rods. This action breaks the grid lateral wire. The lateral wire, in breaking, necks down in the vicinity of the break point whereby the end of the lateral wire of a grid is of smaller diameter than the remainder thereof. Since all of the notches cf the side rods are the same size, the end of the lateral wire in the last notch of one grid and in the first notch of the next grid in a stick of grids, does not fill their respective notches. Therefore, the ends of the lateral wire may not be held firmly in their notches after the peening thereof, whereby in the sizing process, mentioned above, the ends of the lateral wire may pull out or their notches.

Furthermore, in breaking, the lateral wire does not always hrs 1-; at .he same distance from the clamping or holding means. Therefore, different lengths of wire, or tails, extend laterally beyond the last notch of a grid. If the grid lateral wire breaks too close to the clamping means, the tail on a grid may be too long and it be so long that the vacuum tube having that grid as an element thereof be short-circuited by the tail tou g another tube element. Also, if the grid lateral Wire brealis off too close to the clamping means, the remaining grid lateral wire beyond the clamp will not reach to the grid side rods and will not be caught in the notch therein to tart winding the next individual grid. In such case, the grid winding machine or lathe will cease winding grids until it is adjusted manually.

It is a principal object of our invention to provide an improved apparatus and method for continuously wind ing vacuum tube grids.

More particularly it is an object of our invention to provide such an apparatus and method for severing the grid lateral wire after each grid in a stick of grids has been wound and automatically start the winding of the next rid in the stick of grids without having loose lateral wires between grids on the finished stick.

Another object of our invention is to provide an apparatus and method which insures that the grid lateral wire for each grid is of substantially uniform diameter throughout the length of the wound lateral.

It is a further object of our invention to provide such an apparatus and method which insures that the beginning of the lateral wire in each grid wil be peened to the side rods to the same extent as the intermediate portion of the lateral wire of each grid.

It is an object of our invention to provide a method and means for notching a moving solid medium without substa- .ial interference with the movement thereof.

it is a still further object to provide such an apparatus and method for severing the grid lateral wire after each id in a stick of grids has been wound so that sufficient aforesaid objects are accomplished by feeding the grid lateral wire through a notching means and then through a clamping or holding means on its way to be wound in the notches in the grid side rods. The grid lateral wire is notched without slowing the feeding thereof at such a point that upon later clamping thereof, the lateral wire wi l breal: oil at the notch therein just beyond the last notch in a side rod for an individual grid. The notch in grid lateral Wire is made deep enough so that the grid lateral wire will not break due to the strain therein while winding a grid butwill break readily, and without substantial necling at the notch, upon clamping thereof. Upon proper adjustment of the notching and clamping means, no tails, or very short tails of uniform length from grid to grid will be produced. The resulting tails, if any, extend only slight y from the side rods. Also, portion of the grid lateral wire extending from the clamp towards the rotating side rods will be long enough to start winding the next individual grid auto- 'rnatically upon release of the clamping means.

The invention m y be best understood in connection with the draw forming a part hereof in which:

l is a plan view of apparatus made according to this invention and showing the spacial relation of the notching means to the clamping means and to-the grid winding lathe;

FIG. 2 is a partial elevation partly in section of a clamping means and a grid winding lathe while winding a grid;

FIG. 3 is a partial elevation partly in section of the clamping means and the grid Winding lathe shortly after the. grid lateral wire has been broken away;

FIG. 4 is a side elevational view partly broken away of the lateral wire notching means;

PEG. 5 is a side elevation of the notching means in its notching position;

FIG. 6 is a side elevation after the completion of the notching operation; and,

of Le notching means just FIG. 7 is a diagram showing the timing means for energizing the notching and clamping solenoids in accordance with this invention.

The grid lateral wire notching means of this invention and its relation to the clamping and winding apparatus is shown in FIG. 1. The apparatus includes a base 8 on which is mounted a pair of lateral wire pressure pads 10 and 12, a lateral wire clamp 13 and the solenoid 2i) and lever 22 for operating the clamp 18. The pressure pad 10 is mounted on the end of table 8 away from clamping means 18. The other pressure pad 12, is also mounted on table 8 for cooperation with pressure pad 10 and is adjustable with respect thereto by means of screw adjustment 58, for adjusting the tension on the grid lateral wire which runs between them. The grid lateral wire is wound in the usual Way on side rods 26 and 28 supported in the arbor or mandrel 24 of the grid winding lathe thus providing the stick of grids 30 as well as the individual grids 32 of the stick of grids 36. For convenience, the notching wheel 34 and the peening wheel 36 are not shown in FIG. 1. FIGS. 2 and 3 are referred to for illustration of positions of these wheels with relation to the arbor and side rods. The several elements of the device are described separately below.

1 The arbor 24 of the grid winding lathe is provided with a pair of parallely extending longitudinal grooves diametrically arranged therein into which the grid side rods fit. This arbor is rotated in a clockwise direction by a motor (not shown). Grid side rods 26 and 28 fit the grooves in the arbor 24 and are advanced together along the length thereof by suitable apparatus (not shown). As shown in FIG. 2, a notching wheel 34 is positioned to cut notches alternately and successively in side rods 26 and 28 as they are rotated past the notching wheel 34 and a peening wheel 36 is arranged to peen the most recently cut notch in the side rod. As shown inJFIG- 3, the peening and notching wheels may be moved out of peening and notching position by means not shown.

The grid winding lathe is conventional and no further illustration of the grid lathe and of the parts thereof is considered necessary.

The clamping means 18 comprising a stationary clamping jaw 38 mounted on the end of table 8 and a rotatable clamping jaw 40 pivoted on table 8 by means of pivot 42 and cooperating with said stationary jaw 38. A metal strip 44 is secured to the upper face of clamping jaw 38 by means of a clamp 46 and extends across 22 is in contact with the lever end 46' of jaw 40 and the other end thereof is in contact with the shaft 54 of rotary solenoid 20.

In accordance with the invention, a notcher 14, which will be described in detail below in connection with FIGS.

. 4, 5 and,6, is mounted ,on the base 8 between the pressure pads 10, 12 and clamp 18, and in line therewith so that the grid lateral wire 33may be strung through these three elements. A solenoid mounted on the base and having a crank lever 82 is provided to operate the notcher.

Turning to FIGS. 4, Sand 6, the notcher'14 com prises a hollow'cylinder having an, integral closure for the bottom thereof and a detachable closure .(not shown) for the top' thereof. .A' notching pin 62 having an upper threaded portion-64 and a lowerenlarged chisel shaped portion 66 extends through the cylinder 60.. The threaded'portion 64 extends througha hole'in the detach'able closure (not shown) and the enlarged portion 66extends through a hole in the bottom .closure' A washer68, fitting the threaded portion 64 and butting on the end of the. enlarged portion 66 fits in a slidable man her in the cylinder 60. A relatively strong compression spring 760 bears between washer 63 and the upper closure of cylinder 68. A knurled nut 72 is threaded on the threaded portion 64 of the pin 62 and a relatively weak compression spring 74 bears between the knurled nut 72 and the upper closure of the cylinder 69. The relatively weak spring 74 tends to move the pin 62 upwardly and the relatively strong spring tends to move the pin 62 downwardly. The knurled nut is adjusted longitudinally of the threaded portions 64 of the pin 62 to such a position that the pin 62 has arr equilibrium or balance 1 rest postion, in which the chisel portion 66 clears the grid lateral wire 33 as shown in FIG. 6. A cross-head 76 having a slot 78 therein is threaded onto the top of pin 62.

A rotary solenoid 16 is provided for operating the notcher 14. This solenoid 16 has an arm 82 which is rotated in a clockwise direction upon energization of the solenoid. The arm 82 has a pin 84 extending laterally from the end of the arm and into the slot 78 in the crosshead 76. An anvil 86 is mounted on table 8 below the chisel end 66 of pin 62. V

The circuit for energizing the solenoids 16 and 20 is 7 shown in FIG. 7. In this figure, the voltage source is connected to solenoid 16 by way of the switch 88 shown held in closed position by cam 90. The solenoid 20 is connected to the supply of electricity by way of switch 92. Cam 94 is provided for closing the switch 92 at the proper time. Cams and 94 are rotated at the same speed as indicated by the dotted line connecting them. The cams are rotated by the motor that turns the arbor 24 of FIGS. 1, 2 and 3. The cams are rotated at a speed such that the solenoids 16 and 20 are each energized once at the completion of each individual grid of the stick of grids.

. The operation of the above-described device is as follows:

The lateral wire 33 is threaded between pressure pads 1i and 12 and between anvil 86 and the lower end or chisel end 66 of pin 62. The lateral wire is further threaded between the jaws 3S and 40 of brake or clamp 18 and to a point above the middle of arbor 24. The

notching wheel 34 and peening wheel 36 are adjusted to notching and peening positions as shown in FIG. 2. The arbor 24 rotates clockwise, carrying side rods 26 and 28 past the notching wheel 34, whereby notches are formed in these side rods. ince the side rods are evenly'fed along the direction of their length, the notches are formed at even intervals and alternately in the side rods. As the first notch in a side rod arrives in an upper position in its rotation, the lateral wire catches in the first notch whereby it is peened into the notch by peening wheel 36. As the side rods continue to rotate and advance, a helix of lateral wire is wound on the siderods. After a predetermined number of turns of the arbor 24, cam 90 rotates to the position, as shown in FIG. 7, whereby it closes switch 88, energizing rotary solenoid 16. The arm 82 of the rotary solenoid rotates clockwise, taking the position shown in FIG. 4. By this rotation, energy from the solenoid 16 is stored in spring 70 by compression thereof and weaker compression springs 74 is permitted to expand. At the proper instant, cam 90 rotates to the point where switch 38 is opened, deenergized rotating solenoid'16. Upon deenergization of the solenoid 16, the energy stored in the spring 70 is released. The spring 76 therefore drives pin62 downwardly beyond the balance point of spring 7 0 and 74, compressing spring 74,

and until the chisel part 66 of pin 62 cuts a notch in the movinglateral wire'33 beneath the pin thereby decreasing its lateral dimension or diameter at the notch. The notching position of the notcherfis shown in FIG. 5. The

7 pin immediately bounces upwardly and spring 74 raises and holds pin 62 at the equilibrium point where pressure by spring74 balances pressure due to spring 70.

s,151,ese

At this equilibrium position, the pin clears the moving lateral wire 33. This position of the notcher is shown in FIG. 6. Thus, the lateral wire 33 is notched with practically no interference with the motion thereof.

In the mean time, cam 94 continues to rotate and it soon reaches the point where it closes switch 92. Closure of switch 92 energizes rotary solenoid 29. As the shaft 54, of rotary solenoid 26 rotates, it also moves axially in a direction away from the solenoid 2% sin ciently far so as to cause rotation of lever 22 about its pivot and it thereby rotates jaw 49 about its respective pivot, to clamp lateral wire 33, preventing further motion thereof. Since arbor 24 continues to rotate, lateral wire 33 is stretched and. breaks at the notch therein. Upon timing of cams 90 and94, the notch in the lateral wire and therefore the break therein, will be just past the top of the arbor 24, as shown in FIG. 3 and just past the vertical axis 12' of the arbor 24 as shown so that the lateral wire will overlie the notch when a side rod is positioned on the vertical axis. The notching and peening wheels are moved outwardly while the arbor continues to turn and the side rods continues to be fed longitudinally. Cams 90 and 94 continue to rotate, releasing switch 92 and deenergizing solenoid 29 thereby releasing clamp 13. As shown in HS. 3, the end of the lateral wire 33 is in a proper position to be caught in a notch in a side rod when the notching and peening wheels are moved back to notching and peening position and a cycle has been completed.

What is claimed is:

1. Apparatus for winding individual grids on a grid stick comprising an arbor, means for feeding a side rod to said arbor and longitudinally of its length, means for rotating said arbor and said side rod, means for feeding a grid lateral wire along a path to said arbor and for fixing said lateral wire to said side rod, means for notching said grid lateral wire at a point in said path, and means along said path for clamping said grid lateral wire to prevent further feeding thereof to said arbor when a grid has been wound and while said arbor is rotating whereby said grid lateral wire is severed at the notch.

made by said notching means to form a single grid.

2. A grid lathe for winding a stick of grids comprising side rods with spaced individual grids of lateral wire Wound on said side rods, said lathe comprising an elongated rotatable arbor for supporting said side rods, means for longtiudinally advancing said side rods, means for notching said side rods, means for feeding a grid lateral wire to the notches in said side rod as said arbor rotates and as said side rods advance, means for peening smd notches after reception thereof of said grid lateral wire for securing said lateral wire, means for notching said grid lateral wire as it is being fed, and means between said lateral wire notching means and said arbor to prevent further feeding of said grid lateral wire after the notching thereof, whereby said grid lateral wire breaks at the notch therein to form an individual grid.

3. Apparatus for producing a stick of grids which comprises means for feeding a grid side rod along the direction of its length and for continuously rotating it about an axis displaced from and parallel to said side rod, means to notch said side rod at a plurality of points along its length as it is fed along its length, means to feed a grid lateral Wire into one of said notches, means to notch said grid lateral wire as it is being fed to said side rod, means to apply tension to said grid lateral wire sufiicient to cause it to break at the notch therein, said means to notch said grid lateral wire and said means to apply tension being so adjusted that said grid lateral wire breaks close to the side rod and at such a point that the end of said severed lateral wire being fed is touched by said side rod during continued rotation thereof, whereby said lateral wire will enter a further notch in said side rod and commence winding another grid of said stick of grids.

4. Apparatus for producinga stick of spaced individual grids which comprises means for feeding grid side rods along the direction of their lengths and for continuously rotating them about an axis parallel to said side rods, means for notching said side rods at points along their lengths, means for feeding a grid lateral Wire to said side rods and into the notches, means for notching said grid lateral wire while it is being fed to said side rods, means between said means for feeding said side rods and the grid lateral notching means for applying tension to said grid lateral wire sufficient to cause the lateral wire to break at the notch therein, said means for notching said grid lateral wire and said means for applying tension being so adjusted that said grid lateral wire breaks close to a side rod and at such point that the end of said lateral wire being fed to said side rods overlies one of said side rods during continued rotation thereof, whereby said lateral wire will enter a further notch in said one of said side rods and commence winding another grid of said stick of grids when said peening means fixes the severed end of said lateral wire in said further notch.

5. Apparatus for winding spaced individual grids on a grid stick comprising: an elongated rotatable arbor, means for feeding side rods to said arbor to be supported thereon and for advancing said side rods longitudinally thereof, means for feeding a grid lateral wire to said side rods while said arbor is rotating and said side rods advancing, means associated with said arbor for fixing said lateral wire to said side rods, means associated with said feeding means for decreasing the transverse dimension of said lateral wire as it is being fed, and means positioned adjacent the grid lateral wire for preventing further feeding of said grid lateral wire when the portion of decreased transverse dimension of said grid lateral Wire reaches said arbor to sever said lateral wire at the portion of decreased transverse dimension to form an individual grid.

6. Apparatus for winding spaced individual grids on a grid stick comprising: an elongated rotatable arbor, means for feeding side rods to said arbor to be supported thereon and for advancing said side rods longitudinally thereof, means for feeding a grid lateral wire to said side rods while said arbor is rotating said side rods advancing, means associated with said arbor for fixing said lateral wire to said side rods, means associated with said feeding means for notching said lateral wire as it is being fed, and means between said lateral wire notching means and said arbor to prevent further feeding of said grid lateral wire when the notch portion of said grid lateral wire reaches said arbor to sever said lateral wire at the notch therein to form an individual grid, and means connected to said notching means and to said means for preventing further feeding of said grid lateral wire for controlling the notching and severing operations.

7. A grid winding apparatus for winding a stick of grids comprising side rods with spaced individual grids of lateral wire wound on said side rods, said apparatus comprising an elongated rotatable arbor for supporting said side rods, means for longitudinally advancing said side rods, means adjacent said arbor for notching said side rods, means for feeding a grid lateral wire to said side rods as said arbor rotates and as said side rods advance to lay said lateral wire in said notches, and means adjacent said arbor for peening said notches after reception therein of said grid lateral wire for fixing said grid lateral wire in said notches, means adjacent the path of said lateral wire for notching said lateral wire as it is being fed to said side rods, and brake means between the lateral wire notcher and said arbor for preventing feeding of the grid lateral wire while said arbor is rotating whereby said grid lateral wire is severed at the notch therein to form an individual grid, and control means associated wiLh said lateral wire feeding means and said brake means to cause the severed end of the lateral wire being fed to overlie said arbor and a notch in a side rod when said lateral wire is severed whereby the winding of a second grid may 7 be initiated upon peening of the severed end of the lateral wire being fed into said last notch.

8. A grid Winding apparatus for winding a stick of grids comprising side rods with spaced individual grids of lateral Wire wound on said side rods, said apparatus comprising an arbor for supporting said side rods, means for feeding a grid lateral Wire along a path to said side rods and winding said lateral Wires on said side rods and fixing said lateral Wire to said side rods, means adjacent the path of said lateral Wire for notclling said lateral Wire as it is being fed to said side rods, and brake means between said lateral wire notch means and said arbor for preventing feeding of the grid lateral vvire While said lateral Wire is being wound on said side rods to sever said lateral wire at the notch therein to form an individual grid, and control means connected with said lateral wire feeding means and said brake means to cause the severed end of the lateral Wire being fed to overlie said arbor and a notch in a side rod whereby the Winding of a second grid may be initiated upon peening of the severed end of the lateral Wire being fed into said last notch.

References Cited in the file of this patent UNITED STATES PATENTS 1,975,155 Keller Oct. 2, 1934 1,978,108 Howald et a1. Oct. 23, 1934 2,441,228 Schneider et al May .11, 1948 2,630,174 Poteet Mar. 3, 1953 2,657,456 Moody Nov. 3, 1953 2,719,543 Maurer Oct. 4, 1955 3,008,365 McNabb Nov. 14, 1961 3,037.533 Chase June 5, 1962 FOREIGN PATENTS 161,001 Australia Aug. 8, 1955 

1. APPARATUS FOR WINDING INDIVIDUAL GRIDS ON A GRID STICK COMPRISING AN ARBOR, MEANS FOR FEEDING A SIDE ROD TO SAID ARBOR AND LONGITUDINALLY OF ITS LENGTH, MEANS FOR ROTATING SAID ARBOR AND SAID SIDE ROD, MEANS FOR FEEDING A GRID LATERAL WIRE ALONG A PATH TO SAID ARBOR AND FOR FIXING SAID LATERAL WIRE TO SAID SIDE ROD, MEANS FOR NOTCHING SAID GRID LATERAL WIRE AT A POINT IN SAID PATH, AND MEANS ALONG SAID PATH FOR CLAMPING SAID GRID LATERAL WIRE TO PREVENT FURTHER FEEDING THEREOF TO SAID ARBOR WHEN A GRID HAS BEEN WOUND AND WHILE SAID ARBOR IS ROTATING WHEREBY SAID GRID LATERAL WIRE IS SEVERED AT THE NOTCH MADE BY SAID NOTCHING MEANS TO FORM A SINGLE GRID. 